A method for treating a super large karst cavity behind a tunnel wall

Abstract

Disclosed is a method for treating a super-large karst cavity behind a tunnel wall, comprising the following steps: cleaning up the slag in a predetermined area of ​​the karst cave; reinforcing the karst cavity roof in the predetermined area by using an anchor net spraying method, and reinforcing the karst cavity roof outside the predetermined area by using shotcrete; setting a first support unit and a second support unit at a second predetermined distance on one side of the tunnel excavation contour; filling concrete between the first support columns to form a first retaining wall, and filling concrete between the second support columns to form a second retaining wall; backfilling concrete between the first retaining wall and the outer contour of the tunnel and between the second retaining wall and the outer contour of the tunnel; backfilling the karst cavity on the first and second retaining walls away from the tunnel side with waste slag; backfilling and sealing the reserved channel. The method for treating a super-large karst cavity behind a tunnel wall provided in this specification can effectively ensure construction safety without affecting the normal construction progress of the tunnel.

Description

Technical Field

[0001] The present invention relates to the technical field of underground passage construction, and in particular to a method for treating a super-large karst cavity behind a tunnel wall. Background Art

[0002] When railway tunnels pass through mountainous areas, special geological conditions such as caves are often encountered. Caves are underground dissolution phenomena formed by the chemical action and mechanical destruction of soluble rock layers by surface water and groundwater. When caves appear on one side and below the tunnel construction layer, they are more likely to have an adverse impact on tunnel construction, and large-scale caves often require targeted treatment. If a tunnel passes through a giant cave cavity, both the early construction and later operations will face high risks such as block falling from the top of the cave and settlement of the backfill soil at the bottom. How to quickly and economically deal with large karst cavities encountered in tunnel construction while ensuring construction progress and safety has always been a difficult problem in the engineering community. Summary of the invention

[0003] In view of the deficiencies in the prior art, one purpose of this specification is to provide a method for treating a super-large karst cavity behind a tunnel wall, which can effectively ensure construction safety without affecting the normal construction progress of the tunnel.

[0004] To achieve the above-mentioned purpose, the embodiment of this specification provides a method for treating a super-large karst cavity behind a tunnel wall, comprising the following steps:

[0005] Cleaning up the slag in a predetermined area of ​​the cave; wherein the predetermined area is an area within a range of a first predetermined distance from one side of the tunnel excavation contour;

[0006] The top plate of the cavity within the predetermined area is reinforced by using an anchor mesh spraying method, and the top plate of the cavity outside the predetermined area is reinforced by using a shotcrete spraying method;

[0007] A first support unit and a second support unit are arranged along the extension direction of the tunnel at a second predetermined distance on one side of the tunnel excavation profile; wherein the second predetermined distance is smaller than the first predetermined distance; the first support unit includes a plurality of first support columns arranged along the extension direction, the second support unit includes a plurality of second support columns arranged along the extension direction, the spacing between adjacent first support columns and second support columns is greater than a third predetermined distance, the spacing between adjacent first support columns is smaller than the third predetermined distance, and the spacing between adjacent second support columns is smaller than the third predetermined distance;

[0008] Filling concrete between the first support columns to form a first retaining wall, and filling concrete between the second support columns to form a second retaining wall; wherein the distance between the first retaining wall and the second retaining wall is equal to a third predetermined distance;

[0009] Backfilling concrete between the first retaining wall and the outer contour of the tunnel and between the second retaining wall and the outer contour of the tunnel; wherein the distance between the backfilled concrete between the first retaining wall and the outer contour of the tunnel and the backfilled concrete between the second retaining wall and the outer contour of the tunnel is equal to a third predetermined distance, and the first retaining wall, the second retaining wall and the backfilled concrete together form a reserved channel;

[0010] Backfilling the cavities of the first retaining wall and the second retaining wall on the side away from the tunnel with waste slag;

[0011] The reserved channel is backfilled and closed.

[0012] As a preferred implementation, after the step of performing the reinforcement treatment and before the step of backfilling the concrete, monitoring measurement points for monitoring the abnormality of the roof are arranged on the roof of the cave.

[0013] As a preferred embodiment, in the step of cleaning the slag in the predetermined area of ​​the cave, the cleaning length is 5 to 7 m each time, the cleaning route for the top of the cave is horizontally inclined downward at 45° each time, and the temporary slope is protected by 10 cm thick shotcrete; after the slag is cleaned, the height of the cave meets the working space requirements of the anchor drilling rig.

[0014] As a preferred embodiment, the anchor mesh spraying method adopts 4m long φ22 mortar anchor rods, the spacing of the mortar anchor rods is 1.2m×1.2m, the steel mesh adopts φ8 steel bars, the grid spacing is 25cm×25cm, the sprayed concrete strength is C25, and the thickness is 20cm; the concrete sprayed by the spraying concrete method has a strength of C25 and a thickness of 10cm.

[0015] As a preferred implementation, the first predetermined distance is 5 to 7 m; the second predetermined distance is 4 to 6 m; the third predetermined distance is 3 to 5 m; further, the first predetermined distance is 6 m; the second predetermined distance is 5 m; and the third predetermined distance is 4 m.

[0016] As a preferred embodiment, a plurality of the first support columns are evenly arranged along the extension direction, and a distance between adjacent first support columns is no more than 2 meters; a plurality of the second support columns are evenly arranged along the extension direction, and a distance between adjacent second support columns is no more than 2 meters.

[0017] As a preferred implementation, the number of the first support columns is equal to the number of the second support columns, and the spacing between adjacent first support columns is equal to the spacing between adjacent second support columns.

[0018] As a preferred implementation, the first support column and the second support column are seamless steel pipe support columns, and C20 concrete is poured into the first support column and the second support column.

[0019] As a preferred implementation, a support base is provided below the first support column and the second support column. The material of the support base is C20 concrete, and the depth of the support base is 2 meters.

[0020] As a preferred embodiment, in the step of backfilling concrete and the step of backfilling and sealing, C20 concrete is used;

[0021] In the waste slag backfilling step, the waste slag from the tunnel waste dump is used for backfilling, and the backfilling is carried out in layers from low to high. For the local area within 2m from the top plate of the cave that cannot be fully filled with waste slag, pumped C20 concrete is used to fill it.

[0022] Beneficial effects:

[0023] The method for processing the super-large karst cavity behind the tunnel wall provided in this embodiment uses anchor net spraying and shotcrete spraying for reinforcement after cleaning the slag, which can effectively prevent construction workers from being directly exposed to the danger of cavity collapse during construction work, thereby ensuring the safety of construction workers; at the same time, by backfilling the first and second retaining walls and the outer contour of the tunnel, the tunnel wall is reinforced to ensure the progress of tunnel construction; and then the karst cavity on the side of the first and second retaining walls away from the tunnel is backfilled with waste slag through the reserved channel, which greatly speeds up the construction progress and effectively saves construction time. The backfilling process of the super-large karst cavity in this application does not affect the normal construction progress of the tunnel, so that the construction progress is guaranteed.

[0024] With reference to the following description and the accompanying drawings, the specific embodiments of the present invention are disclosed in detail, indicating the manner in which the principles of the present invention can be adopted. It should be understood that the embodiments of the present invention are not limited in scope thereby.

[0025] Features described and / or illustrated with respect to one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments.

[0026] It should be emphasized that the term “include / comprises” when used herein refers to the presence of features, integers, steps or components, but does not exclude the presence or addition of one or more other features, integers, steps or components. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without paying creative labor.

[0028] Figure 1 A flowchart of the steps of a method for treating a super-large karst cavity behind a tunnel wall provided in this embodiment;

[0029] Figure 2 A plan view of the backfilling of the cavity behind the tunnel wall after the treatment method of the super-large karst cavity behind the tunnel wall provided in this embodiment, and Figure 2 The structure is before step S70;

[0030] Figure 3 This is a longitudinal cross-sectional view of the backfilling of the cavity behind the tunnel wall after the treatment method of the super-large karst cavity behind the tunnel wall provided in this embodiment, Figure 2 for Figure 3 A top view of Figure 2 Omitted Figure 3 The part on the right side of the first or second retaining wall.

[0031] Description of reference numerals:

[0032] 1. Tunnel; 11. Outer contour; 2. First support unit; 21. First support column; 3. Second support unit; 31. Second support column; 4. First retaining wall; 5. Second retaining wall; 6. Reserved channel; 7. Support base; 8. C20 concrete backfill structure; 9. Waste slag backfill structure. DETAILED DESCRIPTION

[0033] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0034] It should be noted that when an element is referred to as being "disposed on" another element, it may be directly on the other element or there may be another element centered thereon. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be another element centered thereon at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation method.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0036] See also Figure 1 The embodiment of the present application provides a method for treating a super-large karst cavity behind a tunnel wall, comprising the following steps:

[0037] Step S10: cleaning the slag in the predetermined area of ​​the cave.

[0038] The predetermined area is the area within the range of a first predetermined distance from one side of the tunnel 1 excavation contour. The first predetermined distance is 5 to 7 meters. Preferably, the first predetermined distance is 6 meters. Figure 3 As shown, the karst cave of the present application is located on the right side of the tunnel 1 , so in step S10 , it is necessary to clean up the karst cave slag within 6m on the right side of the excavation outline of the tunnel 1 .

[0039] In step S10, the slag needs to be cleaned to the bottom of the tunnel. The cleaning length each time is 5 to 7 meters. The slope of the slag cleaning is controlled at 1:1, that is, the cleaning route for the top of the cave each time is horizontally inclined 45 degrees to the lower right. The temporary slope is protected by 10 cm thick shotcrete. After the slag is cleaned, the height of the cavity needs to meet the working space requirements of the anchor drill to facilitate the subsequent step S20.

[0040] Step S20: The top plate of the cavity within the predetermined area is reinforced by using an anchor mesh spraying method, and the top plate of the cavity outside the predetermined area is reinforced by using a shotcrete spraying method.

[0041] This step can support the cave roof. In step S20, the anchor mesh spraying method uses 4m long φ22 mortar anchor rods, the spacing of the mortar anchor rods is 1.2m (circular) × 1.2m (vertical), the steel mesh uses φ8 steel bars, the grid spacing is 25cm × 25cm, the sprayed concrete strength is C25, and the thickness is 20cm. The concrete sprayed on the cave roof outside the predetermined area has a strength of C25 and a thickness of 10cm.

[0042] Step S30: a first support unit 2 and a second support unit 3 are arranged along the extension direction of the tunnel 1 at a second predetermined distance on one side of the excavation profile of the tunnel 1 .

[0043] Wherein, the second predetermined distance is smaller than the first predetermined distance. The second predetermined distance is 4 to 6 meters. Furthermore, the second predetermined distance is 5 meters. Figure 2 As shown, the first support unit 2 may include a plurality of first support columns 21 arranged along the extension direction, and the second support unit 3 may include a plurality of second support columns 31 arranged along the extension direction.

[0044] Preferably, a plurality of first support columns 21 are evenly spaced and arranged along the extension direction. The spacing between adjacent first support columns 21 is no greater than 2 meters. A plurality of second support columns 31 are evenly spaced and arranged along the extension direction. The spacing between adjacent second support columns 31 is no greater than 2 meters. The number of the first support columns 21 is equal to the number of the second support columns 31. The spacing between adjacent first support columns 21 is equal to the spacing between adjacent second support columns 31.

[0045] Specifically, the first support column 21 and the second support column 31 are both seamless steel pipe support columns. The diameter of the seamless steel pipe support column can be 630 mm. C20 concrete is poured into the first support column 21 and the second support column 31. A support base 7 can be provided below the first support column 21 and the second support column 31. The material of the support base 7 is C20 concrete. The depth of the support base 7 is 2 meters. The support base 7 can be a cuboid, and its length, width and height can all be 2 meters. The use of the support base 7 can make the support structure formed by the first support column 21 and the second support column 31 more stable.

[0046] In this embodiment, the distance between the adjacent first support columns 21 and the second support columns 31 is greater than the third predetermined distance, thereby providing space for the subsequent reserved channel 6. The distance between the adjacent first support columns 21 is less than the third predetermined distance, and the distance between the adjacent second support columns 31 is less than the third predetermined distance, ensuring that the support structure formed by the first support columns 21 and the second support columns 31 is more stable. The third predetermined distance is 3 to 5 meters. Further, the third predetermined distance is 4 meters.

[0047] Step S40 : filling concrete between the first support columns 21 to form a first retaining wall 4 , and filling concrete between the second support columns 31 to form a second retaining wall 5 .

[0048] The spacing between the first retaining wall 4 and the second retaining wall 5 is equal to the third predetermined distance. Specifically, the first retaining wall 4 can be formed by spraying concrete between the first support columns 21, and the second retaining wall 5 can be formed by spraying concrete between the second support columns 31.

[0049] Step S50 : backfilling concrete between the first retaining wall 4 and the outer contour 11 of the tunnel 1 and between the second retaining wall 5 and the outer contour 11 of the tunnel 1 .

[0050] The distance between the backfilled concrete between the first retaining wall 4 and the outer contour 11 of the tunnel 1 and the backfilled concrete between the second retaining wall 5 and the outer contour 11 of the tunnel 1 is equal to the third predetermined distance. The first retaining wall 4, the second retaining wall 5 and the backfilled concrete together form a reserved channel 6, so that the waste residue generated by the excavation of the tunnel 1 can be transported through the reserved channel 6 and filled into the right side of the first retaining wall 4 and the second retaining wall 5 in the subsequent step S60. In step S50, C20 concrete is used.

[0051] Step S60: backfilling the karst cavity of the first retaining wall 4 and the second retaining wall 5 away from the tunnel 1 with waste slag.

[0052] In step S60, since a reserved channel 6 is provided, the waste residue from the abandoned slag field of tunnel 1 can be transported to the right cave cavity through the reserved channel 6 for backfilling, and the backfilling work does not affect normal construction. Backfilling can be carried out in layers from low to high. For the local area within 2m from the cave top plate that cannot be fully filled with waste residue, pumped C20 concrete is used to fill it. In this step, the cave cavity on the right side of the reserved channel 6 is also backfilled with waste residue without reserving a gap or channel.

[0053] like Figure 3 As shown, step S60 can form the slag backfill structure 9 and the partial C20 concrete backfill structure 8 located above the slag backfill structure 9. The remaining partial C20 concrete backfill structure 8, i.e., the C20 concrete backfill structure 8 located between the outer contour 11 of the tunnel 1 and the first retaining wall 4 or the second retaining wall 5, is formed by step S50.

[0054] Step S70: backfilling and sealing the reserved channel 6.

[0055] Specifically, after the karst cavity outside the right side of the first retaining wall 4 and the second retaining wall 5 is backfilled, the reserved channel 6 is backfilled and closed with C20 concrete.

[0056] The method for processing the super-large karst cavity behind the tunnel wall provided in this embodiment is particularly suitable for the backfill construction of the super-large karst cavity behind the tunnel wall. After cleaning the false slag, the anchor net spraying method and the shotcrete spraying method are used for reinforcement treatment, which can effectively prevent the construction personnel from being directly exposed to the danger of cavity collapse during construction work, thereby ensuring the safety of the construction personnel; at the same time, by backfilling the first and second retaining walls 4 and 5 and the outer contour 11 of the tunnel 1, the wall of the tunnel 1 is reinforced to ensure the progress of tunnel construction; and then the karst cavity of the first and second retaining walls 4 and 5 away from the side of the tunnel 1 is backfilled with waste slag through the reserved channel 6, which greatly speeds up the construction progress and effectively saves construction period. The backfilling process of the super-large karst cavity in this application does not affect the normal construction progress of the tunnel 1, so that the construction progress is guaranteed.

[0057] In this embodiment, after step S20 and before step S50, monitoring and measuring points for monitoring abnormalities of the top plate are arranged on the top plate of the cave. Thus, in the process of backfilling, if there is an abnormality, the construction personnel can be evacuated in time and corresponding reinforcement measures can be taken. During the backfilling operation, the safety of the construction is guaranteed by monitoring and measuring the position of the top plate of the cave.

[0058] It should be noted that, in the description of this specification, the terms "first", "second", etc. are only used for descriptive purposes and to distinguish similar objects. There is no order of precedence between the two, and they cannot be understood as indicating or implying relative importance. In addition, in the description of this specification, unless otherwise specified, the meaning of "plurality" is two or more.

[0059] Any numerical value cited herein includes all values ​​of lower and upper values ​​that increase by one unit from the lower limit to the upper limit, and there is at least a two-unit interval between any lower value and any higher value. For example, if the value of the quantity of a component or a process variable (such as temperature, pressure, time, etc.) is stated to be from 1 to 90, preferably from 20 to 80, and more preferably from 30 to 70, the purpose is to illustrate that values ​​such as 15 to 85, 22 to 68, 43 to 51, 30 to 32 are also explicitly listed in the specification. For values ​​less than 1, one unit is appropriately considered to be 0.0001, 0.001, 0.01, 0.1. These are merely examples that are intended to be clearly expressed, and it can be considered that all possible combinations of numerical values ​​listed between the lowest value and the highest value are clearly stated in the specification in a similar manner.

[0060] Unless otherwise indicated, all ranges include the endpoints and all numbers between the endpoints. "About" or "approximately" used with a range applies to both endpoints of the range. Thus, "about 20 to 30" is intended to cover "about 20 to about 30", including at least the specified endpoints.

[0061] All articles and references disclosed, including patent applications and publications, are incorporated herein by reference for all purposes. The term "consisting essentially of..." to describe a combination should include the identified elements, ingredients, parts or steps and other elements, ingredients, parts or steps that do not substantially affect the basic novel characteristics of the combination. The use of the terms "comprising" or "including" to describe a combination of elements, ingredients, parts or steps herein also contemplates embodiments that consist essentially of these elements, ingredients, parts or steps. By using the term "may", it is intended to indicate that any attribute described that "may" include is optional.

[0062] Multiple elements, ingredients, parts or steps can be provided by a single integrated element, ingredient, part or step. Alternatively, a single integrated element, ingredient, part or step can be divided into separate multiple elements, ingredients, parts or steps. The disclosure "one" or "an" used to describe an element, ingredient, part or step is not intended to exclude other elements, ingredients, parts or steps.

[0063] It should be understood that the above description is for illustration and not for limitation. Many embodiments and many applications beyond the examples provided will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of the present teachings should not be determined with reference to the above description, but should be determined with reference to the appended claims and the full scope of equivalents possessed by such claims. For the purpose of comprehensiveness, all articles and references, including disclosures of patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the preceding claims is not intended to be a waiver of the subject matter, nor should it be considered that the inventors did not consider the subject matter to be part of the disclosed inventive subject matter.

Claims

1. A method for treating a super-large karst cavity behind a tunnel wall, characterized in that: The following steps are involved: Cleaning up the slag in a predetermined area of ​​the cave; wherein the predetermined area is an area within a range of a first predetermined distance from one side of the tunnel excavation contour; The top plate of the cavity within the predetermined area is reinforced by using an anchor mesh spraying method, and the top plate of the cavity outside the predetermined area is reinforced by using a shotcrete spraying method; A first support unit and a second support unit are arranged along the extension direction of the tunnel at a second predetermined distance on one side of the tunnel excavation profile; wherein the second predetermined distance is smaller than the first predetermined distance; the first support unit includes a plurality of first support columns arranged along the extension direction, the second support unit includes a plurality of second support columns arranged along the extension direction, the spacing between adjacent first support columns and second support columns is greater than a third predetermined distance, the spacing between adjacent first support columns is smaller than the third predetermined distance, and the spacing between adjacent second support columns is smaller than the third predetermined distance; Filling concrete between the first support columns to form a first retaining wall, and filling concrete between the second support columns to form a second retaining wall; wherein the spacing between the first retaining wall and the second retaining wall is equal to a third predetermined distance; Backfilling concrete between the first retaining wall and the outer contour of the tunnel and between the second retaining wall and the outer contour of the tunnel; wherein the distance between the backfilled concrete between the first retaining wall and the outer contour of the tunnel and the backfilled concrete between the second retaining wall and the outer contour of the tunnel is equal to a third predetermined distance, and the first retaining wall, the second retaining wall and the backfilled concrete together form a reserved channel; Backfilling the cavities of the first retaining wall and the second retaining wall on the side away from the tunnel with waste slag; The reserved channel is backfilled and closed.

2. The method for treating the super-large karst cavity behind the tunnel wall according to claim 1 is characterized in that: After the step of performing the reinforcement treatment and before the step of backfilling the concrete, monitoring measurement points for monitoring the abnormality of the top plate are arranged on the top plate of the cave.

3. The method for treating the super-large karst cavity behind the tunnel wall according to claim 1, characterized in that: In the step of cleaning the slag in the predetermined area of ​​the cave, the cleaning length is 5 to 7 m each time, and the cleaning route for the top of the cave is horizontally inclined downward by 45 degrees each time. The temporary slope is protected by 10 cm thick shotcrete; after the slag is cleaned, the height of the cave meets the working space requirements of the anchor drilling rig.

4. The method for treating the super-large karst cavity behind the tunnel wall according to claim 1, characterized in that: The anchor mesh spraying method adopts 4m long φ22 mortar anchor rods, the spacing of the mortar anchor rods is 1.2m×1.2m, the steel mesh adopts φ8 steel bars, the grid spacing is 25cm×25cm, the sprayed concrete strength is C25, and the thickness is 20cm; the concrete sprayed by the spraying concrete method has a strength of C25 and a thickness of 10cm.

5. The method for treating the super-large karst cavity behind the tunnel wall according to claim 1, characterized in that: The first predetermined distance is 5 to 7 m; the second predetermined distance is 4 to 6 m; the third predetermined distance is 3 to 5 m; further, the first predetermined distance is 6 m; the second predetermined distance is 5 m; and the third predetermined distance is 4 m.

6. The method for treating the super-large karst cavity behind the tunnel wall according to claim 1, characterized in that: A plurality of the first support columns are evenly arranged along the extension direction, and a distance between adjacent first support columns is no greater than 2 meters; a plurality of the second support columns are evenly arranged along the extension direction, and a distance between adjacent second support columns is no greater than 2 meters.

7. The method for treating the super-large karst cavity behind the tunnel wall according to claim 6, characterized in that: The number of the first support columns is equal to the number of the second support columns, and the interval between adjacent first support columns is equal to the interval between adjacent second support columns.

8. The method for treating the super-large karst cavity behind the tunnel wall according to claim 6, characterized in that: The first support column and the second support column are seamless steel pipe support columns, and C20 concrete is poured into the first support column and the second support column.

9. The method for treating a super-large karst cavity behind a tunnel wall according to claim 6, characterized in that: A support base is provided below the first support column and the second support column. The material of the support base is C20 concrete, and the depth of the support base is 2 meters.

10. The method for treating a super-large karst cavity behind a tunnel wall according to claim 1, characterized in that: In the step of backfilling concrete and the step of backfilling and sealing, C20 concrete is used; In the waste slag backfilling step, the waste slag from the tunnel waste dump is used for backfilling, and the backfilling is carried out in layers from low to high. For the local area within 2m from the top plate of the cave that cannot be fully filled with waste slag, pumped C20 concrete is used to fill it.

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